Engine starter



F. WOOD.

ENGINE STARTER APPLICATION FILED NOV. a. 1918.

Patented Feb. 17,1920.

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ENGINE SIAR'IER.

APPLICATION FILED NOV. s. 1918.

UNITED srATns PATENT orrion.

FREDERICK WOOD, OF BIRMINGHAM, ENGLAND, ASSIG-IFIUR TO THE ELECTRIC AIlD ORDNANCE ACGEfiSORIES COMPANY LIMITED, 035 BIRMINGHAM, ENGLAND.

ENGI E-Mamas.

Specification of Letters Patent.

Patented Feb. 1'7, 1920.

Application filed November 8, 1918. Serial No. 261,628.

edcertain new and useful Improvements in Engine-Starters, of which the followingis I a specification.

This invention relates to engine starters of that type comprising an electric or other motor which drives an externally screwthreaded shaft upon which is mounted for longitudinal movement thereon, an lnternally screw-threaded pinion or gear member adapted, by the rotation of the shaft, to be traversed in anaXial direction into engagement with a driven member onthe fly-wheel or other part connected with the engine shaft; the shock when the pinion or the like moves into gear being relieved or absorbed by a yielding buflier device (such as a suit ably arranged coiled spring) with which the said pinion engages.

The object of the present invention is to provide an improved form of yielding buffer device in which provision is made; for giving a rigidor solid drive after the spring or yielding device has been compressed to a certain point.

According to the invention the butter dc vice comprises a member (independent of the pinion or gear member) which slidably mounted upon the shaft andwhich is adapted to beengaged and moved longitudinally by the saidpinion or} gear m'ember when it moves into gear, and a fixed member or abutment upon the shaft with which the slidingmember engages to give a solid drive, a spring or a cushion of air being interposed between the said member to absorb the shock prior to the engagement of the said members. a Figure 1 of the accompanying drawings is a sectional elevation with the pinion out of mesh. I i

Fig.2 is a similar viewuwith the pinion. ingear; J Figs. 3 and4 representmodifications. Referring to Figs. 1 and 2, theouter end of the electric motor shaft 1 is reduced in diameter at 2 and has secureduponiasuch as by a bolt 3, an externally screw-threaded sleeve 4: whose inner end bears against the shoulder 5 at the junction oi the reduced portion of the shaft with the part of larger diameter, thelatter being of slightlysmaller I diameter than the external diameter of the screw-threaded sleeve. Upon the latter is freely mounted an internally screw-threaded pinion 6 whose internal diameter is slightly greater than the diameter of the larger portion of the shaft 1. The said pinion is adapted to be traversed, by the rotation of the screw-threaded sleeve, in a longitudinal direction into mesh with a driven member 7 upon the flywheel or other part connected with the engine shaft. Mounted upon the larger diameter of the motor shaft, adjacent toand normally bearing against the inner end of the screw-threaded sleeve 4:, is a sliding collar 8 having at its outer end a circumferential flange or piston 9 provided with an annular wall or rim 14L movable within a dashpot cylinder 10 carried by an abutment plate 11. The latter is formed with a centralboss IQfiXQCl upon the shaft 1 and extending toward the sliding collar 8 but being normally maintained separated from the latter, as shown in F1 1, by a volute-coiledspiral buffer spring 13 interposed between the said parts 9, 11, the largest coil of this spring being positioned within the rim 1a of the piston and the smallerend being; supported by the boss 12.

When the pinion 6 moves into engagement with the driven member 7 its inner end engageswith the outer face of the sliding collar 8 andmoves the latter inward along the shaft, thereby compressing the spring 13 in order to absorb or cushion the shock due to the driven member taking up the drive. The sliding collar 8 continues to move inward until it engages with the central boss 12 of the fixed abutment plate, as in Fig. 2, when further longitudinal movement of the pinion is arrested and a solid drive obtained.

Owing to the annular wall 14 of the piston 9 being a close fit within the casing or cylinder 10 the air within the latter is compressed, giving a dash-pot effect, and assist ing the spring in its cushioning action.

According to the arrangement represented in Fig. 3, the position of the spiral bufier spring 13 may be reversed, the flange 9 of the sliding'collar 8 carrying the cylinder 10 and being recessed upon its inner face to re pression of the air by the piston 9 moving within the cylinder 10 may be solely relied upon to give the cushioning efiect, the buffer spring being dispensed with and only alight spring employed for returning-the sliding collar 8- toits normal position.

In some cases the dashpot device may be dispensed with, 'and only "the buffer spring employed for absorbing the shock.

Having fully described my invention, what 7 I'desire to claim and secure by Letters Pat- ,nally by the gear member, an abutment upon the said shaft with which the sliding memher is adapted to engage to give a solid drive, and cushioning means interposed between the said'slidingmemberand the abutment.

. 2. An engine starter comprising a driven member connected with an engine shaft, a drive shaft having a part of reduced diameter; an externally screw-threaded sleeve 7 secured upon said reduced part ofthe shaft,

7 said sleevebeing of larger external diameter than the larger diameter of the shaft;

' an internally screwthreaded:gear member mounted upon lthe'shaft for longitudinal movement thereon; a sliding. member on the larger diameter of the motor-driven shaft normally abutting against the en-dof the screw-threaded sleeve and adapted to be engaged and moved longitudinally by the gear member when'the latter travels into mesh with-the driven member; a fixed abutment upon the larger diameter oflthe shaft with i which the sliding member-is adapted to engagetoqgive a solid :drive; andcushioning means interposed between the said sliding memberand the abutment. i

'3. I An engine starter comprising a driven member connected with an engineshaft, an

externally screw-threaded driven shaft, an

internally screw-threaded gear member mounted upon sa d shaft for'l'ongitudmal movement thereon and adapted, by the rotationof the shaft, vto be. traversed axially into; driving I engagement. with the driven member, a sliding member onthe said shaft adapted to beengaged and moved'longr tudinally'by the-gearrmember, an abutment upon the said shaft with which the sliding member is adapted to engage to give a solid drive, and a- .dashpot cushioning device comprising relatively. movingpiston and cylindermembers one. of which is carried by the sliding member while the other is carried by the abutment.

at. A11 engine starter comprising a driven member connected with an engine shaft, an externally screw-threaded driven shaft, an internally screw-threaded gear member mounted upon said shaft for longitudinal movement thereon and adapted, by the rotation of the shaft, to be traversed. axially into driving engagement vith the driven by the said sliding member while the other is carried by the fixed abutment.

,5. An engine starter comprising a driven member connected with an engine shaft; a driven shaft having a part of reduced diameter; an externally screw-threaded sleeve secured upon said reduced part of the shaft, said sleeve being of larger external diameter than the larger diameter of the shaft; an internally screw-threaded gear member mounted upon the shaft for longitudinal movement thereon: a slidin member on the larger diameter of the motor-driven shaft 1 normally abutting against the end of the screw-threaded. sleeve and adapted to be cnged and moved longitudinally bv the gear member when the latter travels into mesh with the driven member; a fixed abutment upon the larger diameter of the shaft with which the sliding member engages to give a solid drive; and a cushioning spring in terposed between the sliding member and the abutment.

6. An engine starter comprising a driven member connected with an engine shaft; a driven shaft having a part of reduced diameter; an externally screw-tlnfeadcd sleeve secured upon said reduced part of the shaft,

said sleeve being of larger external diameter than the larger diameter of the shaft: an internally screw-threaded gear member mounted upon the shaft for longitudinal movement thereon, a sliding member on the larger diameter of the motor-driven shaft normally abutting against the end of the screw-threaded sleeve and adapted to be engaged and moved longitiulinally by the gear member when the latter travels into mesh with the driven member, a fixed abutment upon-the lan er diameter of the shaft with which the sliding member engages to give a solid drive, and a dashpot cushioning device comprising relatively moving piston and cylinder members one of which iscarried by the sliding member while the other is carried by the fixed abutment.

7. An engine starter comprising a driven member connected with an engine shaft, an externally screw-threaded driven shaft, an internally screw-threaded gear member mounted upon said shaft for longitudinal movement thereon and adapted by the rotation of the shaft to be traversed axially into driving engagement with said driven mem- 7 her, a sliding member on said shaft adapted to be engaged and moved longitudinally by said gear member, said sliding member constituting the piston of a dash-pot cushioning device, and a fixed abutment upon said shaft with which 1 said sliding member is adapted to engage to give a solid drive, said fixed abutment being an integral part of the cylinder of a dash-pot cushioning de vlee.

In witness whereof I have hereunto set my hand in the presence of two subscribing witnesses.

FREDERICK WOOD.

Witnesses HARRY GsMoNn PRATT, W. N. SHERRE'IT; 

